A known laminated core is disclosed in JP2003-528557A and JP2002-262496A. That is, a motor stator core formed by laminating multiple sheet parts, each of which is shaped as an arc, in a zigzag manner as is disclosed in JP2003-528557A. More precisely, the sheet parts are arranged next to each other and joined with each other to form a laminated core. Substantially arc-shaped sheet part segments with a peripheral length corresponding to an angle α=360°/n, n being a whole positive number and greater than or equal to two, are produced by stamping. The ‘n’ numbers of these sheet part segments are then arranged in one plane to produce a sheet part, the sheet parts arranged next to each other being connected and/or welded with at least one connecting element.
JP2002-262496A discloses a core structure of a rotary electric machine. Recess and projection portions provided on end faces in the circumferential direction of each fan-shaped segmented core are fitted to each other to form an annular rotor core. Then, laminations of the predetermined number of annular rotor cores form a cylindrical rotor core. Each block of the cylindrical rotor cores forms laminations in a bricklaying manner by an arrangement of respective portions where the recess and projection portions are meted to each other in a staggered manner in the circumferential direction.
However, according to the aforementioned JP2003-528557A and JP2002-262496A, the arc-shaped sheet parts or the fan-shaped segmented cores are required to be arranged in the staggered manner with a predetermined angle in the circumferential direction. In addition, contacting portions between the arc-shaped sheet parts or those between the fan-shaped segmented cores are displaced in the circumferential direction among layers so that the rotor core is unified and prevented from separating off. Therefore, in doing so, laminating process of the arc-shaped sheet parts or the fan-shaped segmented cores is troublesome, and may cause an increase of a laminating time. As a result, a cost of manufacturing a motor may increase. Further, according to JP2002-262496A, a connecting process in an axial direction is required for a connection between the recess and projection portions provided on the end faces in the circumferential direction of each fan-shaped segmented core, thereby increasing the laminating process.
Thus, a need exists for a laminated core of a rotary electric machine in which a time for a laminating process can be reduced and a mechanically high strength can be obtained.